Summary: Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is one of the most commonly altered tumor suppressor genes in human cancers. It has been shown that tumor susceptibility is highly sensitive to cellular PTEN levels, thereby highlighting the importance of molecular mechanisms for PTEN regulation. Recent research has uncovered a novel mechanism for post-transcriptional regulation of PTEN via a network of microRNAs (miRNAs) and competing endogenous RNAs (ceRNAs). Currently known ceRNAs that regulate PTEN are limited to protein-coding mRNAs and a quantitative framework for modeling PTEN regulation by ceRNAs is lacking. The project proposes to develop computational and experimental approaches for the discovery and analysis of both non-coding and coding ceRNAs of PTEN. The proposed research will lead to the identification of multiple ceRNAs of PTEN and focus on their role in controlling cellular PTEN levels and their impact on tumor susceptibility. The long-term objective is to develop novel therapeutic approaches for cancer based on elevating cellular PTEN levels using ceRNA-based regulation. The specific aims are to: 1) Develop a quantitative model for kinetics and regulation of PTEN by ceRNAs; 2) Develop quantitative models of post-transcriptional regulation of PTEN by ceRNA networks; and 3) Develop protocols for controlling PTEN using ceRNAs and determine the impact on tumor susceptibility. This project involves the innovative integration of approaches from different disciplines and tools such as single-cell assays, stochastic modeling, machine learning, and bioinformatics to analyze regulation of PTEN via ceRNAs. The development of quantitative models and tools for analysis of ceRNA-based regulation, will significantly impact current and future research aimed at understanding its role in diverse cellular processes, thereby significantly impacting the field beyond PTEN function. The project will strengthen collaboration between different departments at UMass Boston and DF/HCC, and will provide excellent interdisciplinary training and mentorship for students and researchers involved. Project Co-Leads, Zarringhalam and Kulkarni, are mentoring several undergraduate students at UMass Boston who are currently working on the project. Students have written Honors theses, given talks based on their research at undergraduate conferences, and are co-authors on multiple presentations at prestigious international conferences. Providing ample opportunity for research experiences for students from underrepresented backgrounds is a top priority of the project, and the project Co-Leads will work diligently with the U54 Research Education Core to facilitate these experiences. Besides the positives arising from interdisciplinary training for students in cutting-edge research, the wide dissemination of the results will also contribute positively to the UMass Boston-DF/HCC U54 Partnership, attract external funding and lead to the development of a strong cancer research program at UMass Boston.